1. Field of the Invention.
This invention relates to closures for metallurigal vessel pouring apertures and more particularly, although not exclusively, to closure members for tapholes of metal producing or processing vessels such as basic oxygen steelmaking (BOS) vessel.
2. Description of the Prior Art.
A problem in the tapping of BOS vessels, for example, is that, as the vessels are tilted towards the tapping position, an initial flow of slag will leave the vessel by the taphole, causing difficulties in disposal, prior to the metal contained in the BOS vessel being tapped into the waiting receptacle as it reaches the level of the taphole.
A number of systems has been devised in which a plugging device is inserted or fitted to the outside (cold end) of the taphole to prevent slag egress but when they are used there is a possibility that the taphole will initially fill with slag which will not be entirely displaced by metal when tapping begins.
It is an object of the present invention to overcome or at least substantially reduce the above mentioned problem.